The cancer was discovered last month after Gwynn, 50, underwent his third bout of surgery since 1997 to remove a tumor on his parotid gland, which pumps saliva into the mouth.

The former San Diego Padres star said he faces seven to eight weeks of five-day-a-week radiation treatments and once-a-week chemotherapy treatments, the Union-Tribune reported. Gwynn said doctors told him they feel they caught the cancer early and “there was not much of it there.”

“They say this is a slow-moving but aggressive form of cancer,” Gwynn told the paper. “I’m going to be aggressive and not slow moving in treating this.”

Gwynn suspects the cancer could be linked to his career-long practice of using chewing tobacco.

“I haven’t discussed that with the doctors yet, but I’m thinking it’s related to dipping,” said Gwynn, who resumed using chewing tobacco after the first two surgeries.

Gwynn is San Diego State’s baseball coach, and the school confirmed Gwynn’s condition to The Associated Press. Gwynn plans to return to his alma mater, which he has coached since 2003. He retired from the majors in 2001 after 20 seasons with the Padres, in which he won a National League record-tying eight batting championships and was named to the All-Star Game 16 times.